The present invention relates to novel structural and pharmacological analogs cis-17,18-didehydroprostacyclin (PGI.sub.3). In particular, the present invention relates to prostacyclin-type compounds wherein the 6,9.alpha.-epoxy-oxygen of prostacyclin is replaced by a nitrogen atom. Cis-17,18-didehydroprostacyclin exhibits the following structure and carbon atom numbering: ##STR1##
For discussion of prostacyclin, its biological activities, its methods of chemical synthesis, and the conventions for depicting formulas of such compounds, see U.S. Pat. No. 4,097,489, issued June 27, 1978, the relevant disclosure of which is incorporated here by reference. Also incorporated by reference from U.S. Pat. No. 4,097,489 are the conventions of nomenclature employed therein, especially those described on columns 2 and 6-12.